\(\left(7x-11\right)^3=2^5.5^2+200.\)
\(\left(7x-11\right)^3=800+200\)
\(\left(7x-11\right)^3=1000\)
\(\left(7x-11\right)^3=10^3\)
\(\Leftrightarrow7x-11=10\)
\(\Leftrightarrow7x=10+11\)
\(\Leftrightarrow7x=21\)
\(\Leftrightarrow x=3\)
Vậy ...........
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Tìm x :
( 7x - 11 )3 = 25 . 52 + 200
<=> ( 7x - 11 )3 = 32 . 25 + 200
<=> ( 7x - 11 )3 = 800 + 200
<=> ( 7x - 11 )3 = 1000
<=> ( 7x - 11 )3 = 103
<=> 7x - 11 = 10
<=> 7x = 10 + 11
<=> 7x = 21
<=> x = 21 : 7
<=> x = 3
Vậy x = 3
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